Based on the solubility chart, which of the listed salts is the most soluble at 25 °c?
a) sodium nitrate
b) sodium chloride
c) potassium nitrate
d) potassium chlorate

this is the picture
i would say potassium iodide but its not a choice

Acylinder with a movable piston contains 11.7 moles of a monatomic ideal gas at a pressure of 1.32×10^5 pa. the gas is initially at a temperature of 300 k. an electric heater adds 43200 j of energy into the gas while the piston moves in such a way that the pressure remains constant. cp=20.79 j k^−1 mol^−1 for a monatomic ideal gas, and that the number of gas molecules is equal to avogadro's number (6.022×10^23) times the number of moles of the gas. (a) what is the temperature of the gas after the energy is added? (b) what is the change in volume of the gas? (c) how much work is done by the gas during this process?

How do you know how many valence electrons an atom has?

Which is a substance that can be separated by physical means and is not the same throughout